dsmethod.c

Go to the documentation of this file.

/******************************************************************************
 *
 * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2012, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acdispat.h"
#include "acinterp.h"
#include "acnamesp.h"
#ifdef  ACPI_DISASSEMBLER
#include <acpi/acdisasm.h>
#endif

#define _COMPONENT          ACPI_DISPATCHER
ACPI_MODULE_NAME("dsmethod")

/* Local prototypes */
static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_method_error
 *
 * PARAMETERS:  status          - Execution status
 *              walk_state      - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Called on method error. Invoke the global exception handler if
 *              present, dump the method data if the disassembler is configured
 *
 *              Note: Allows the exception handler to change the status code
 *
 ******************************************************************************/

acpi_status
acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
{
    ACPI_FUNCTION_ENTRY();

    /* Ignore AE_OK and control exception codes */

    if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
        return (status);
    }

    /* Invoke the global exception handler */

    if (acpi_gbl_exception_handler) {

        /* Exit the interpreter, allow handler to execute methods */

        acpi_ex_exit_interpreter();

        /*
         * Handler can map the exception code to anything it wants, including
         * AE_OK, in which case the executing method will not be aborted.
         */
        status = acpi_gbl_exception_handler(status,
                            walk_state->method_node ?
                            walk_state->method_node->
                            name.integer : 0,
                            walk_state->opcode,
                            walk_state->aml_offset,
                            NULL);
        acpi_ex_enter_interpreter();
    }

    acpi_ds_clear_implicit_return(walk_state);

#ifdef ACPI_DISASSEMBLER
    if (ACPI_FAILURE(status)) {

        /* Display method locals/args if disassembler is present */

        acpi_dm_dump_method_info(status, walk_state, walk_state->op);
    }
#endif

    return (status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_method_mutex
 *
 * PARAMETERS:  obj_desc            - The method object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a mutex object for a serialized control method
 *
 ******************************************************************************/

static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
{
    union acpi_operand_object *mutex_desc;
    acpi_status status;

    ACPI_FUNCTION_TRACE(ds_create_method_mutex);

    /* Create the new mutex object */

    mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
    if (!mutex_desc) {
        return_ACPI_STATUS(AE_NO_MEMORY);
    }

    /* Create the actual OS Mutex */

    status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
    if (ACPI_FAILURE(status)) {
        return_ACPI_STATUS(status);
    }

    mutex_desc->mutex.sync_level = method_desc->method.sync_level;
    method_desc->method.mutex = mutex_desc;
    return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_begin_method_execution
 *
 * PARAMETERS:  method_node         - Node of the method
 *              obj_desc            - The method object
 *              walk_state          - current state, NULL if not yet executing
 *                                    a method.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
 *              increments the thread count, and waits at the method semaphore
 *              for clearance to execute.
 *
 ******************************************************************************/

acpi_status
acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
                   union acpi_operand_object *obj_desc,
                   struct acpi_walk_state *walk_state)
{
    acpi_status status = AE_OK;

    ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);

    if (!method_node) {
        return_ACPI_STATUS(AE_NULL_ENTRY);
    }

    /* Prevent wraparound of thread count */

    if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
        ACPI_ERROR((AE_INFO,
                "Method reached maximum reentrancy limit (255)"));
        return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
    }

    /*
     * If this method is serialized, we need to acquire the method mutex.
     */
    if (obj_desc->method.info_flags & ACPI_METHOD_SERIALIZED) {
        /*
         * Create a mutex for the method if it is defined to be Serialized
         * and a mutex has not already been created. We defer the mutex creation
         * until a method is actually executed, to minimize the object count
         */
        if (!obj_desc->method.mutex) {
            status = acpi_ds_create_method_mutex(obj_desc);
            if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
            }
        }

        /*
         * The current_sync_level (per-thread) must be less than or equal to
         * the sync level of the method. This mechanism provides some
         * deadlock prevention
         *
         * Top-level method invocation has no walk state at this point
         */
        if (walk_state &&
            (walk_state->thread->current_sync_level >
             obj_desc->method.mutex->mutex.sync_level)) {
            ACPI_ERROR((AE_INFO,
                    "Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%u)",
                    acpi_ut_get_node_name(method_node),
                    walk_state->thread->current_sync_level));

            return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
        }

        /*
         * Obtain the method mutex if necessary. Do not acquire mutex for a
         * recursive call.
         */
        if (!walk_state ||
            !obj_desc->method.mutex->mutex.thread_id ||
            (walk_state->thread->thread_id !=
             obj_desc->method.mutex->mutex.thread_id)) {
            /*
             * Acquire the method mutex. This releases the interpreter if we
             * block (and reacquires it before it returns)
             */
            status =
                acpi_ex_system_wait_mutex(obj_desc->method.mutex->
                              mutex.os_mutex,
                              ACPI_WAIT_FOREVER);
            if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
            }

            /* Update the mutex and walk info and save the original sync_level */

            if (walk_state) {
                obj_desc->method.mutex->mutex.
                    original_sync_level =
                    walk_state->thread->current_sync_level;

                obj_desc->method.mutex->mutex.thread_id =
                    walk_state->thread->thread_id;
                walk_state->thread->current_sync_level =
                    obj_desc->method.sync_level;
            } else {
                obj_desc->method.mutex->mutex.
                    original_sync_level =
                    obj_desc->method.mutex->mutex.sync_level;
            }
        }

        /* Always increase acquisition depth */

        obj_desc->method.mutex->mutex.acquisition_depth++;
    }

    /*
     * Allocate an Owner ID for this method, only if this is the first thread
     * to begin concurrent execution. We only need one owner_id, even if the
     * method is invoked recursively.
     */
    if (!obj_desc->method.owner_id) {
        status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
        if (ACPI_FAILURE(status)) {
            goto cleanup;
        }
    }

    /*
     * Increment the method parse tree thread count since it has been
     * reentered one more time (even if it is the same thread)
     */
    obj_desc->method.thread_count++;
    return_ACPI_STATUS(status);

      cleanup:
    /* On error, must release the method mutex (if present) */

    if (obj_desc->method.mutex) {
        acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);
    }
    return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_call_control_method
 *
 * PARAMETERS:  thread              - Info for this thread
 *              this_walk_state     - Current walk state
 *              op                  - Current Op to be walked
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Transfer execution to a called control method
 *
 ******************************************************************************/

acpi_status
acpi_ds_call_control_method(struct acpi_thread_state *thread,
                struct acpi_walk_state *this_walk_state,
                union acpi_parse_object *op)
{
    acpi_status status;
    struct acpi_namespace_node *method_node;
    struct acpi_walk_state *next_walk_state = NULL;
    union acpi_operand_object *obj_desc;
    struct acpi_evaluate_info *info;
    u32 i;

    ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);

    ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
              "Calling method %p, currentstate=%p\n",
              this_walk_state->prev_op, this_walk_state));

    /*
     * Get the namespace entry for the control method we are about to call
     */
    method_node = this_walk_state->method_call_node;
    if (!method_node) {
        return_ACPI_STATUS(AE_NULL_ENTRY);
    }

    obj_desc = acpi_ns_get_attached_object(method_node);
    if (!obj_desc) {
        return_ACPI_STATUS(AE_NULL_OBJECT);
    }

    /* Init for new method, possibly wait on method mutex */

    status = acpi_ds_begin_method_execution(method_node, obj_desc,
                        this_walk_state);
    if (ACPI_FAILURE(status)) {
        return_ACPI_STATUS(status);
    }

    /* Begin method parse/execution. Create a new walk state */

    next_walk_state = acpi_ds_create_walk_state(obj_desc->method.owner_id,
                            NULL, obj_desc, thread);
    if (!next_walk_state) {
        status = AE_NO_MEMORY;
        goto cleanup;
    }

    /*
     * The resolved arguments were put on the previous walk state's operand
     * stack. Operands on the previous walk state stack always
     * start at index 0. Also, null terminate the list of arguments
     */
    this_walk_state->operands[this_walk_state->num_operands] = NULL;

    /*
     * Allocate and initialize the evaluation information block
     * TBD: this is somewhat inefficient, should change interface to
     * ds_init_aml_walk. For now, keeps this struct off the CPU stack
     */
    info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
    if (!info) {
        return_ACPI_STATUS(AE_NO_MEMORY);
    }

    info->parameters = &this_walk_state->operands[0];

    status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
                       obj_desc->method.aml_start,
                       obj_desc->method.aml_length, info,
                       ACPI_IMODE_EXECUTE);

    ACPI_FREE(info);
    if (ACPI_FAILURE(status)) {
        goto cleanup;
    }

    /*
     * Delete the operands on the previous walkstate operand stack
     * (they were copied to new objects)
     */
    for (i = 0; i < obj_desc->method.param_count; i++) {
        acpi_ut_remove_reference(this_walk_state->operands[i]);
        this_walk_state->operands[i] = NULL;
    }

    /* Clear the operand stack */

    this_walk_state->num_operands = 0;

    ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
              "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
              method_node->name.ascii, next_walk_state));

    /* Invoke an internal method if necessary */

    if (obj_desc->method.info_flags & ACPI_METHOD_INTERNAL_ONLY) {
        status =
            obj_desc->method.dispatch.implementation(next_walk_state);
        if (status == AE_OK) {
            status = AE_CTRL_TERMINATE;
        }
    }

    return_ACPI_STATUS(status);

      cleanup:

    /* On error, we must terminate the method properly */

    acpi_ds_terminate_control_method(obj_desc, next_walk_state);
    if (next_walk_state) {
        acpi_ds_delete_walk_state(next_walk_state);
    }

    return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_restart_control_method
 *
 * PARAMETERS:  walk_state          - State for preempted method (caller)
 *              return_desc         - Return value from the called method
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Restart a method that was preempted by another (nested) method
 *              invocation.  Handle the return value (if any) from the callee.
 *
 ******************************************************************************/

acpi_status
acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
                   union acpi_operand_object *return_desc)
{
    acpi_status status;
    int same_as_implicit_return;

    ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);

    ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
              "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
              acpi_ut_get_node_name(walk_state->method_node),
              walk_state->method_call_op, return_desc));

    ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
              "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
              walk_state->return_used,
              walk_state->results, walk_state));

    /* Did the called method return a value? */

    if (return_desc) {

        /* Is the implicit return object the same as the return desc? */

        same_as_implicit_return =
            (walk_state->implicit_return_obj == return_desc);

        /* Are we actually going to use the return value? */

        if (walk_state->return_used) {

            /* Save the return value from the previous method */

            status = acpi_ds_result_push(return_desc, walk_state);
            if (ACPI_FAILURE(status)) {
                acpi_ut_remove_reference(return_desc);
                return_ACPI_STATUS(status);
            }

            /*
             * Save as THIS method's return value in case it is returned
             * immediately to yet another method
             */
            walk_state->return_desc = return_desc;
        }

        /*
         * The following code is the optional support for the so-called
         * "implicit return". Some AML code assumes that the last value of the
         * method is "implicitly" returned to the caller, in the absence of an
         * explicit return value.
         *
         * Just save the last result of the method as the return value.
         *
         * NOTE: this is optional because the ASL language does not actually
         * support this behavior.
         */
        else if (!acpi_ds_do_implicit_return
             (return_desc, walk_state, FALSE)
             || same_as_implicit_return) {
            /*
             * Delete the return value if it will not be used by the
             * calling method or remove one reference if the explicit return
             * is the same as the implicit return value.
             */
            acpi_ut_remove_reference(return_desc);
        }
    }

    return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_terminate_control_method
 *
 * PARAMETERS:  method_desc         - Method object
 *              walk_state          - State associated with the method
 *
 * RETURN:      None
 *
 * DESCRIPTION: Terminate a control method.  Delete everything that the method
 *              created, delete all locals and arguments, and delete the parse
 *              tree if requested.
 *
 * MUTEX:       Interpreter is locked
 *
 ******************************************************************************/

void
acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
                 struct acpi_walk_state *walk_state)
{

    ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);

    /* method_desc is required, walk_state is optional */

    if (!method_desc) {
        return_VOID;
    }

    if (walk_state) {

        /* Delete all arguments and locals */

        acpi_ds_method_data_delete_all(walk_state);

        /*
         * If method is serialized, release the mutex and restore the
         * current sync level for this thread
         */
        if (method_desc->method.mutex) {

            /* Acquisition Depth handles recursive calls */

            method_desc->method.mutex->mutex.acquisition_depth--;
            if (!method_desc->method.mutex->mutex.acquisition_depth) {
                walk_state->thread->current_sync_level =
                    method_desc->method.mutex->mutex.
                    original_sync_level;

                acpi_os_release_mutex(method_desc->method.
                              mutex->mutex.os_mutex);
                method_desc->method.mutex->mutex.thread_id = 0;
            }
        }

        /*
         * Delete any namespace objects created anywhere within the
         * namespace by the execution of this method. Unless:
         * 1) This method is a module-level executable code method, in which
         *    case we want make the objects permanent.
         * 2) There are other threads executing the method, in which case we
         *    will wait until the last thread has completed.
         */
        if (!(method_desc->method.info_flags & ACPI_METHOD_MODULE_LEVEL)
            && (method_desc->method.thread_count == 1)) {

            /* Delete any direct children of (created by) this method */

            acpi_ns_delete_namespace_subtree(walk_state->
                             method_node);

            /*
             * Delete any objects that were created by this method
             * elsewhere in the namespace (if any were created).
             * Use of the ACPI_METHOD_MODIFIED_NAMESPACE optimizes the
             * deletion such that we don't have to perform an entire
             * namespace walk for every control method execution.
             */
            if (method_desc->method.
                info_flags & ACPI_METHOD_MODIFIED_NAMESPACE) {
                acpi_ns_delete_namespace_by_owner(method_desc->
                                  method.
                                  owner_id);
                method_desc->method.info_flags &=
                    ~ACPI_METHOD_MODIFIED_NAMESPACE;
            }
        }
    }

    /* Decrement the thread count on the method */

    if (method_desc->method.thread_count) {
        method_desc->method.thread_count--;
    } else {
        ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
    }

    /* Are there any other threads currently executing this method? */

    if (method_desc->method.thread_count) {
        /*
         * Additional threads. Do not release the owner_id in this case,
         * we immediately reuse it for the next thread executing this method
         */
        ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
                  "*** Completed execution of one thread, %u threads remaining\n",
                  method_desc->method.thread_count));
    } else {
        /* This is the only executing thread for this method */

        /*
         * Support to dynamically change a method from not_serialized to
         * Serialized if it appears that the method is incorrectly written and
         * does not support multiple thread execution. The best example of this
         * is if such a method creates namespace objects and blocks. A second
         * thread will fail with an AE_ALREADY_EXISTS exception.
         *
         * This code is here because we must wait until the last thread exits
         * before marking the method as serialized.
         */
        if (method_desc->method.
            info_flags & ACPI_METHOD_SERIALIZED_PENDING) {
            if (walk_state) {
                ACPI_INFO((AE_INFO,
                       "Marking method %4.4s as Serialized because of AE_ALREADY_EXISTS error",
                       walk_state->method_node->name.
                       ascii));
            }

            /*
             * Method tried to create an object twice and was marked as
             * "pending serialized". The probable cause is that the method
             * cannot handle reentrancy.
             *
             * The method was created as not_serialized, but it tried to create
             * a named object and then blocked, causing the second thread
             * entrance to begin and then fail. Workaround this problem by
             * marking the method permanently as Serialized when the last
             * thread exits here.
             */
            method_desc->method.info_flags &=
                ~ACPI_METHOD_SERIALIZED_PENDING;
            method_desc->method.info_flags |=
                ACPI_METHOD_SERIALIZED;
            method_desc->method.sync_level = 0;
        }

        /* No more threads, we can free the owner_id */

        if (!
            (method_desc->method.
             info_flags & ACPI_METHOD_MODULE_LEVEL)) {
            acpi_ut_release_owner_id(&method_desc->method.owner_id);
        }
    }

    return_VOID;
}